forked from Kolyah35/minecraft-pe-0.6.1
173 lines
7.4 KiB
C
Executable File
173 lines
7.4 KiB
C
Executable File
#ifndef NET_MINECRAFT_CLIENT_RENDERER_CULLING__Frustum_H__
|
|
#define NET_MINECRAFT_CLIENT_RENDERER_CULLING__Frustum_H__
|
|
|
|
//package net.minecraft.client.renderer.culling;
|
|
|
|
/* import static org.lwjgl.opengl.GL11.* */
|
|
|
|
#include "java/nio/FloatBuffer.h"
|
|
|
|
#include "client/MemoryTracker.h"
|
|
|
|
|
|
// Stolen and ported to java from the web somewhere.
|
|
|
|
//***********************************************************************//
|
|
// //
|
|
// - "Talk to me like I'm a 3 year old!" Programming Lessons - //
|
|
// //
|
|
// $Author: DigiBen digiben@gametutorials.com //
|
|
// //
|
|
// $Program: Frustum Culling //
|
|
// //
|
|
// $Description: Demonstrates checking if shapes are in view //
|
|
// //
|
|
// $Date: 8/28/01 //
|
|
// //
|
|
//***********************************************************************//
|
|
|
|
//#include "main.h"
|
|
|
|
// We create an enum of the sides so we don't have to call each side 0 or 1.
|
|
// This way it makes it more understandable and readable when dealing with frustum sides.
|
|
/*public*/ class Frustum: public FrustumData
|
|
{
|
|
/*private*/ static Frustum frustum = /*new*/ Frustum();
|
|
|
|
/*public*/ static FrustumData getFrustum()
|
|
{
|
|
frustum.calculateFrustum();
|
|
return frustum;
|
|
}
|
|
|
|
///////////////////////////////// NORMALIZE PLANE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
|
|
/////
|
|
///// This normalizes a plane (A side) from a given frustum.
|
|
/////
|
|
///////////////////////////////// NORMALIZE PLANE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
|
|
|
|
/*private*/ void normalizePlane(float[][] frustum, int side)
|
|
{
|
|
// Here we calculate the magnitude of the normal to the plane (point A B C)
|
|
// Remember that (A, B, C) is that same thing as the normal's (X, Y, Z).
|
|
// To calculate magnitude you use the equation: magnitude = sqrt( x^2 + y^2 + z^2)
|
|
float magnitude = (float) util.Mth.sqrt(frustum[side][A] * frustum[side][A] + frustum[side][B] * frustum[side][B] + frustum[side][C] * frustum[side][C]);
|
|
|
|
// Then we divide the plane's values by it's magnitude.
|
|
// This makes it easier to work with.
|
|
frustum[side][A] /= magnitude;
|
|
frustum[side][B] /= magnitude;
|
|
frustum[side][C] /= magnitude;
|
|
frustum[side][D] /= magnitude;
|
|
}
|
|
|
|
/*private*/ FloatBuffer _proj = MemoryTracker.createFloatBuffer(16);
|
|
/*private*/ FloatBuffer _modl = MemoryTracker.createFloatBuffer(16);
|
|
/*private*/ FloatBuffer _clip = MemoryTracker.createFloatBuffer(16);
|
|
|
|
/*private*/ void calculateFrustum()
|
|
{
|
|
_proj.clear();
|
|
_modl.clear();
|
|
_clip.clear();
|
|
|
|
// glGetFloatv() is used to extract information about our OpenGL world.
|
|
// Below, we pass in GL_PROJECTION_MATRIX to abstract our projection matrix.
|
|
// It then stores the matrix into an array of [16].
|
|
glGetFloat(GL_PROJECTION_MATRIX, _proj);
|
|
|
|
// By passing in GL_MODELVIEW_MATRIX, we can abstract our model view matrix.
|
|
// This also stores it in an array of [16].
|
|
glGetFloat(GL_MODELVIEW_MATRIX, _modl);
|
|
|
|
_proj.flip().limit(16);
|
|
_proj.get(proj);
|
|
_modl.flip().limit(16);
|
|
_modl.get(modl);
|
|
|
|
// Now that we have our modelview and projection matrix, if we combine these 2 matrices,
|
|
// it will give us our clipping planes. To combine 2 matrices, we multiply them.
|
|
|
|
clip[0] = modl[0] * proj[0] + modl[1] * proj[4] + modl[2] * proj[8] + modl[3] * proj[12];
|
|
clip[1] = modl[0] * proj[1] + modl[1] * proj[5] + modl[2] * proj[9] + modl[3] * proj[13];
|
|
clip[2] = modl[0] * proj[2] + modl[1] * proj[6] + modl[2] * proj[10] + modl[3] * proj[14];
|
|
clip[3] = modl[0] * proj[3] + modl[1] * proj[7] + modl[2] * proj[11] + modl[3] * proj[15];
|
|
|
|
clip[4] = modl[4] * proj[0] + modl[5] * proj[4] + modl[6] * proj[8] + modl[7] * proj[12];
|
|
clip[5] = modl[4] * proj[1] + modl[5] * proj[5] + modl[6] * proj[9] + modl[7] * proj[13];
|
|
clip[6] = modl[4] * proj[2] + modl[5] * proj[6] + modl[6] * proj[10] + modl[7] * proj[14];
|
|
clip[7] = modl[4] * proj[3] + modl[5] * proj[7] + modl[6] * proj[11] + modl[7] * proj[15];
|
|
|
|
clip[8] = modl[8] * proj[0] + modl[9] * proj[4] + modl[10] * proj[8] + modl[11] * proj[12];
|
|
clip[9] = modl[8] * proj[1] + modl[9] * proj[5] + modl[10] * proj[9] + modl[11] * proj[13];
|
|
clip[10] = modl[8] * proj[2] + modl[9] * proj[6] + modl[10] * proj[10] + modl[11] * proj[14];
|
|
clip[11] = modl[8] * proj[3] + modl[9] * proj[7] + modl[10] * proj[11] + modl[11] * proj[15];
|
|
|
|
clip[12] = modl[12] * proj[0] + modl[13] * proj[4] + modl[14] * proj[8] + modl[15] * proj[12];
|
|
clip[13] = modl[12] * proj[1] + modl[13] * proj[5] + modl[14] * proj[9] + modl[15] * proj[13];
|
|
clip[14] = modl[12] * proj[2] + modl[13] * proj[6] + modl[14] * proj[10] + modl[15] * proj[14];
|
|
clip[15] = modl[12] * proj[3] + modl[13] * proj[7] + modl[14] * proj[11] + modl[15] * proj[15];
|
|
|
|
// Now we actually want to get the sides of the frustum. To do this we take
|
|
// the clipping planes we received above and extract the sides from them.
|
|
|
|
// This will extract the RIGHT side of the frustum
|
|
m_Frustum[RIGHT][A] = clip[3] - clip[0];
|
|
m_Frustum[RIGHT][B] = clip[7] - clip[4];
|
|
m_Frustum[RIGHT][C] = clip[11] - clip[8];
|
|
m_Frustum[RIGHT][D] = clip[15] - clip[12];
|
|
|
|
// Now that we have a normal (A,B,C) and a distance (D) to the plane,
|
|
// we want to normalize that normal and distance.
|
|
|
|
// Normalize the RIGHT side
|
|
normalizePlane(m_Frustum, RIGHT);
|
|
|
|
// This will extract the LEFT side of the frustum
|
|
m_Frustum[LEFT][A] = clip[3] + clip[0];
|
|
m_Frustum[LEFT][B] = clip[7] + clip[4];
|
|
m_Frustum[LEFT][C] = clip[11] + clip[8];
|
|
m_Frustum[LEFT][D] = clip[15] + clip[12];
|
|
|
|
// Normalize the LEFT side
|
|
normalizePlane(m_Frustum, LEFT);
|
|
|
|
// This will extract the BOTTOM side of the frustum
|
|
m_Frustum[BOTTOM][A] = clip[3] + clip[1];
|
|
m_Frustum[BOTTOM][B] = clip[7] + clip[5];
|
|
m_Frustum[BOTTOM][C] = clip[11] + clip[9];
|
|
m_Frustum[BOTTOM][D] = clip[15] + clip[13];
|
|
|
|
// Normalize the BOTTOM side
|
|
normalizePlane(m_Frustum, BOTTOM);
|
|
|
|
// This will extract the TOP side of the frustum
|
|
m_Frustum[TOP][A] = clip[3] - clip[1];
|
|
m_Frustum[TOP][B] = clip[7] - clip[5];
|
|
m_Frustum[TOP][C] = clip[11] - clip[9];
|
|
m_Frustum[TOP][D] = clip[15] - clip[13];
|
|
|
|
// Normalize the TOP side
|
|
normalizePlane(m_Frustum, TOP);
|
|
|
|
// This will extract the BACK side of the frustum
|
|
m_Frustum[BACK][A] = clip[3] - clip[2];
|
|
m_Frustum[BACK][B] = clip[7] - clip[6];
|
|
m_Frustum[BACK][C] = clip[11] - clip[10];
|
|
m_Frustum[BACK][D] = clip[15] - clip[14];
|
|
|
|
// Normalize the BACK side
|
|
normalizePlane(m_Frustum, BACK);
|
|
|
|
// This will extract the FRONT side of the frustum
|
|
m_Frustum[FRONT][A] = clip[3] + clip[2];
|
|
m_Frustum[FRONT][B] = clip[7] + clip[6];
|
|
m_Frustum[FRONT][C] = clip[11] + clip[10];
|
|
m_Frustum[FRONT][D] = clip[15] + clip[14];
|
|
|
|
// Normalize the FRONT side
|
|
normalizePlane(m_Frustum, FRONT);
|
|
}
|
|
}
|
|
#endif /*NET_MINECRAFT_CLIENT_RENDERER_CULLING__Frustum_H__*/
|